SEDIMENTARY STRATA AFTER LAST GLACIAL MAXIMUM ON CENTRAL AND SOUTH EAST CHINA SEA SHELF AND ENVIRONMENTAL EVOLUTION

Integrated stratigraphic approaches are adopted for the study of holes of R22, R23, R24, and R25 in the East China Sea Shelf. The deposits after the Last Glacial Maximum are divided into 3 formations from top to bottom i.e. the neritic facies, continental shelf sand ridges facies and the estuarine deltaic facies respectively. The transgressive history of the study area was established as follows: (1) the terrestrial deposit of the layer R25Ⅳwas formed when coastline regressed to 100m of isobath before 17~16 ka BP;(2)the sea level rose after LGM, and sand ridgesⅡin 4 holes was deposited when sea level fluctuated and stabilized during the last deglaciation period of 13~10 ka BP; (3) the silty clayⅠabove the sand ridges was deposited during the period when the sea level has remained in rising from 10 ka BP to present. The regressive stratigraphic sequence and the environmental evolution before LGM are revealed through R25 which is located in a deeper area.